Thank you for your instructions.
I always had problems with “embed /boot/grub/e2fs_stage_5 …”
It was reported as failed.
Windows XP always rewrote the MBR.

Now I used this command in grub, and it worked :-).
Then I typed “install /boot/grub/stage1 (hd0) (hd0)1+17 p (hd0,3)/boot/grub/stage2 /boot/grub/menu.lst”
And it also ran without any problems.
After that grub seems to work as it should and it seems as if windows xp doesn’t anymore rewrite the MBR.